WENNER: BIOLOGY OF DEEP-SEA LOBSTERS 



Other Polychelid Species 



Polycheles validus (A. Milne-Edwards) is found 

 in the eastern and western Atlantic, the Mediter- 

 ranean and Caribbean Seas, and the Gulf of 

 Mexico. Its distribution in the western North At- 

 lantic extends northward to lat. 42° N at 2,211- 

 2,393 m (Firth and Pequegnat see footnote 4). My 

 Middle Atlantic Bight collections recovered 10 P. 

 validus at depths between 1,698 and 2,337 m and 

 temperatures of 3.8'-2.9° C. Males ranged from 21 

 to 48 mm with spermatophores present in gono- 

 pores of two individuals, 32 and 44 mm SCL. Two 

 females were collected, 21 and 28 mm SCL, and 

 both were immature. Small catches of P. validus 

 are best attributed to its deep-living existence, 

 having never been reported shallower than 1,280 

 m. 



Polychelt'sgranulatus(Faxon)has been reported 

 from the Atlantic, Pacific, and Indian Oceans at 

 depths of 347-2,505 m (Firth and Pequegnat see 

 footnote 4). Captures of this species were reported 

 at 349-799 m in the western North Atlantic by 

 Squires.*^ I collected 11 individuals from the Mid- 

 dle Atlantic Bight at depths between 932 (4.4° C) 

 and 2,068 m (3.4 'C). Nine males, none with exter- 

 nal spermatophores, were 16-22 mm SCL. Two 

 immature females 18-28 mm were also captured. 

 The presence of ovigerous fema.\e P. granulatus off 

 the Nova Scotian Shelf at 350-440 m (Squires see 

 footnote 6) and the fact that this species has not 

 been reported from the' Gulf of Mexico or the 

 Carribbean Sea ( Firth and Pequegnat see footnote 

 4) is evidence that reproducing populations of this 

 species occur in the northerly reaches of the west- 

 ern Atlantic. 



DISCUSSION 



Although Stereomastis nana andS.sculpta were 

 both represented in catches from the Middle At- 

 lantic Bight, it is evident that relative abundance 

 and bathymetric distribution of the two species 

 are markedly different. Stereomastis nana was the 

 most abundant species collected, total catches 

 being almost four times greater than those of S. 

 sculpta. Haedrich et al. (1975) collected only S. 

 nana during trawling with a 4.9 m ( 16-fti net on 

 the continental slope south of New England. From 



further trawls in this location, they obtained 92S. 

 nana at 24 stations between 828 and 3,642 m, and 

 only 2 S. sculpta at 2 stations between 1,328 and 

 1,938 m (Haedrich et al.''). Farther north. Squires 

 (see footnote 6) collected 15 S. sculpta off the slope 

 of the Grand Banks at depths of 420-810 m (4.1°- 

 4.5° C). The lack of S. nana in his samples probably 

 resulted from confinement of trawls to depths 

 shallower than 800 m. Stereomastis sculpta is the 

 most commonly caught polychelid in the Gulf of 

 Mexico (Firth and Pequegnat see footnote 4). 

 Roberts (1977) reported density estimates of 394 

 individuals/ha (565-918 m), 343 individuals/ha 

 (1,061-1,829 m), and 88 individuals/ha (2,744- 

 3,256 ml for the northeastern Gulf of Mexico. It 

 appears, therefore, thatS. nana is more abundant 

 in the Middle Atlantic Bight while S. sculpta is 

 more plentiful in southern latitudes. 



Bathymetric distributions of the two species 

 also differ, withS. nana found deeper on the conti- 

 nental slope than S. sculpta. Separate bathymet- 

 ric distributions of these species as proposed by 

 Barnard (1950) formed the basis for rejection of 

 Smith's (1884) hypothesis that S. nana was a 

 dwarf deep-sea form of S. sculpta. 



Stereomastis nana and S. sculpta appear to 

 spawn year round, producing large numbers of 

 small eggs. There is no indication that increased 

 numbers of ovigerous females occur at certain 

 months, as suggested by Santucci (1933) and 

 Squires (see footnote 6). Santucci ( 1933) found the 

 greatest number of ovigerous female Polycheles 

 typhlops were taken between April and July, 

 while mostS. sculptawere ovigerous in May, Oc- 

 tober, and November (Squires see footnote 6). 

 Squires (see footnote 6) concluded from a study of 

 15 individuals that annual breeding occurs in S. 

 sculpta. Collections ofS. nana from my study indi- 

 cate spawning occurs year round. Reproduction in 

 S. sculpta appears also to be year round, but the 

 small sample size limits interpretation of repro- 

 duction in this species. 



There is also no evidence to indicate that the 

 reproductively mature females perform upslope 

 migrations similar to those Santucci (1933) and 

 Bernard (1953) suggested for P. typhlops. These 

 investigators found that ovigerous females and 

 other females with well-developed ovaries ascend 

 to shallower depths where their eggs are released. 



^Squires. H. J. 196.5. Decapod crustaceans of Newfound- 

 land, Labrador and the Canadian eastern Arctic. Fish Res. 

 Board Can. Manuscr. Rep. Ser. 810, 212 p. 



'R. L, Haedrich. G. T. Rowe, and P. T. Polloni, Biological 

 Oceangraphers. Woods Hole Oceanographic Institution, Woods 

 Hole. MA 02543, pers. commun. October 1977. 



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